In the area of wireless communication systems, the need to increase capacity while minimizing possible interference with existing vertically polarized systems, has created a strong demand for horizontally polarized (“H-POL”) antennas.
Directional H-POL antennas tend to be relatively easy to design and may be manufactured cost effectively. However, at present, the design and manufacture of sector H-POL antennas still tends to pose certain challenges. More specifically, conventional sector H-POL antennas are usually configured as waveguide slot antennas. Manufacturing of these antennas tends to be an involved process entailing, among other things, the formation of a waveguide and the cutting of a slot into the waveguide. The manufacturing tolerances for such antennas tend to be quite small. Another known H-POL sector antenna is constructed using wheel dipole technology whereby the antenna is formed by stacking several dipole elements. Assembly of this antenna tends to be complicated.
While certain sector H-POL antennas are available on the market, they tend to be bulky and/or expensive. These drawbacks have tended to discourage use of sector H-POL antennas in establishing base stations for systems including mobile communication, wireless Local Area Network (LAN), Unlicensed National Information Infrastructure (“UNII”), Multi-channel Multi-point Distribution Service (“MMDS”), and Wireless Local Loop (“WLL”) Systems.
One common type of antenna is the dipole antenna which has a quarter wavelength dipole radiator coupled with a balanced transmission line and balun to drive a signal source or a receiver. A conventional dipole antenna has an omni-directional H-Plane radiation pattern and typically, an E-Plane beamwidth of about 80 degrees. This beamwith may be reduced with a reflector. However, it has been found that use of a reflector tends not to significantly affect the E-Plane beamwidth. While adjusting the H-Plane radiation pattern of such dipole antennas is generally known, there currently does not appear to be an effective way to broaden the E-Plane beamwidth of such dipole antennas.
Accordingly, it would be very desirable to have a dipole antenna of relatively simple design, which could be manufactured cost effectively and whose E-Plane beamwidth could be expanded to have a broad range. Such a dipole antenna could be adapted to suit a variety of applications thereby making it very versatile.